This error occurs if the filament never reaches the extruder when you feed the filament from the external spool holder. For an introduction to the external spool holder(also known as "virtual slot"), you can refer to firmware release history (version 01.05.01.00): X1/X1-Carbon and AMS Firmware Release History | Bambu Lab Wiki
07FF_2000_0002_0002 External filament is missing; please load a new filament.
Manually feed the filament into the extruder and click the “retry” (or “resume” depending on the firmware version) button on the screen.
If you want to load filament from AMS instead of the external spool holder, and the printer shows the error, please check:
2. If you are using a P1 series printer, when you click "load" on the display screen, it loads the filament from the external spool holder, requiring you to manually insert the filament into the extruder. Even if the printer is connected to AMS, the filament cannot be loaded from AMS through this operation. If you want to feed from AMS, you need to select the corresponding slot on Bambu Studio and click "Load".